Hi Marek,
On 13/12/2014 14:12, Marek Vasut wrote:
On Friday, December 12, 2014 at 04:03:14 PM, Luca Ellero wrote:
Hi Marek,
On 12/12/2014 13:58, Marek Vasut wrote:
On Friday, December 12, 2014 at 01:43:22 PM, Stefan Roese wrote:
Hi Luca,
On 12.12.2014 13:40, Luca Ellero wrote:
On 10.12.2014 09:24, Luca Ellero wrote:
There is only one pio_word in this DMA transaction so data field must
be 1.
Signed-off-by: Luca Ellero <luca.ell...@brickedbrain.com>
---
drivers/mtd/nand/mxs_nand.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/mtd/nand/mxs_nand.c
b/drivers/mtd/nand/mxs_nand.c index 7a064ab..616c9ca 100644
--- a/drivers/mtd/nand/mxs_nand.c
+++ b/drivers/mtd/nand/mxs_nand.c
@@ -305,7 +305,7 @@ static void mxs_nand_cmd_ctrl(struct mtd_info
*mtd, int data, unsigned int ctrl)
d->cmd.data =
MXS_DMA_DESC_COMMAND_DMA_READ | MXS_DMA_DESC_IRQ |
MXS_DMA_DESC_CHAIN | MXS_DMA_DESC_DEC_SEM |
- MXS_DMA_DESC_WAIT4END | (3 << MXS_DMA_DESC_PIO_WORDS_OFFSET)
| + MXS_DMA_DESC_WAIT4END | (1 <<
MXS_DMA_DESC_PIO_WORDS_OFFSET) |
(nand_info->cmd_queue_len << MXS_DMA_DESC_BYTES_OFFSET);
What error or problem does this incorrect setup cause in your case?
I'm asking since I'm also using this driver in some mx6 system and
have not seen any issues.
As far as I can see, it doesn't seem to cause any issue. But, if you
read the iMX6 Reference Manual (chapter 14.2) this field should reflect
the number of PIO_WORDS appended to the DMA command, in this case 1.
Okay. I just wanted to check if this patch fixes a real problem that you
have experienced. Thanks for the explanation.
Reviewed-by: Stefan Roese <s...@denx.de>
The patch does in fact change the behavior such that it no longer clears
the ECCCTRL and COMPARE registers both on MX28 and on MX6 . Could this
have some impact?
I'm not sure. The manual doesn't tell much about it. Anyway if we want
to clear COMPARE and ECCCTRL register, we should at least ensure that
pio_words 1 and 2 are 0 before executing the DMA chain.
Something like this:
d->cmd.pio_words[1] = 0;
d->cmd.pio_words[2] = 0;
What do you think?
I believe the descriptor is zeroed out in mxs_nand_return_dma_descs(), though
I admit depending on such behavior is pretty iffy.
The question is, does your patch introduce a side-effect ? My proposal would be
to schedule the patch for -next and see what happens. I believe the patch would
be just fine and won't break anything.
What do you think ?
Scheduling the patch for -next it's ok for me.
However there are other two points where pio_words number doesn't
reflect the pio_words really initiated, one is in mxs_nand_read_buf()
and one is in mxs_nand_write_buf(). Each one declares 4 pio_words but
only one is initiated.
I wonder what we should do in this cases.
Regards
--
Luca Ellero
E-mail: luca.ell...@brickedbrain.com
Internet: www.brickedbrain.com
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